There are two baisc types that I use.  The price is the same for either type

Unlike hot blueing, barrels are plugged before parkerizing, as parkerizing is a coating, not a stain.  Parkerizing adds dimension and a rough  finish-neither of which we want in a barrel.  Guns are dis assembled, stripped of old finish, bead blasted, then Parkerized within two hours of blasting.  Any longer wait may result in an uneven finish.

ZINC PHOSPHATE Dark gray color similar to the WWII finish on military guns.  To get the green overtones often seen on vintage Parkerized guns, coat with grease or Cosmoline, let set as long as you can, then wipe off.

MANGANESE PHOSPHATE Black color as seen on modern guns.  It's been my experience that formulas that claim to offer both gray and black in the same can, depending on how long you leave the gun in the solution, don't give you a true black color.  You really need both zinc and manganese based formulas to do the job right.

          HANDGUNS         $245.00 
          WWII GI W/BLUED BBL $260.00.
          RIFLES                 $270.00  
          SHOTGUNS        $285..00 
          Small Parts          $12-35.00
          FAL  G3 AR         $325.00
          M1 GARANDS    $270.00


George Roghaar,Boca Raton, Florida
Firearm Refinishing and Restoration, Parkerizing, Hot Blueing, TR Gun Kote, Recoil Pads
Zinc Parkerizing on a Remington Rand 1911 
The Zinc Phosphate parkerizing is based on a formula from Army TM  9-1861 and I believe is as close to the original finish as possible.
The Manganese Phosphate is a denser finish, and is an improvement over the original WWII zinc phosphate and is appropriate for Korean War and newer guns.

When I parkerize, the gun is bead blasted and then immersed immediately in the soution.  If too much time elapses between the blasting and the immersion, rust can develop which adversly affects the finish.  I have also found that leaving the gun in the solution for 15 minutes after the "fizzing". action,  increases the depth of parkerizing and therefore increases the protection. Takes a little longer, but I want to do the best job possible.